Camera diaphragm setting arrangement



H. PEARCE CAMERA DIAPHRAGM SETTING ARRANGEMENT Feb. 10, 1948.

Original Filed April 20, 1945 ramvms Patented Feb. 10,}948

OFFICE CAMERA DIAPHRAGM SETTING ARRANGEMENT Harold Pearce, Ottawa,Ontario, Canada, assignor to The Honorary Advisory Council forScientific and Industrial Research, Ottawa, Ontario, Canada, acorporation of Canada Original application April 20, 1943, Serial No.483,771. Divided and this application February 23, 1945, Serial No.579,403

1 Claim. 1

This invention relates to diaphragm setting arrangements for cameras. Itis well known that in focussing a camera it is desirable to have thediaphragm open to the ,fullest extent so that maximum light may beobtainedfor focussing purposes. On the other hand for the taking of thepicture it may be necessary to close the diaphragm to quite a smallopening. Particularly if pictures are to be taken in rapid successionthe necessary adjustment of the diaphragm between each picture in orderto obtain maximum light for focussing purposes is a disadvantage.

The present invention has been designed to overcome this disadvantage byproviding an arrangement which makes it possible to predetermine thediaphragm setting at which the picture will be taken, without, however,moving the diaphragm at all, so that the latter remains at its full openposition for focussing but is brought to the proper degree of openingfor the taking of the picture just before the shutter opens. Thearrangement is such that a number of successive pictures may be taken'at the same diaphragm opening without any manipulation of the diaphragmsetting mechanism and yet between each picture the diaphragm will returnto its fully opened position.

The invention is illustrated in more detail in the accompanyingdrawings, in which Figure 1 is a side view of a camera showing theshutter operating lever and the diaphragm setting indicator;

Figure 2 is a partial front view of the camera showing the mechanism forshutting the diaphragm; and

Figure 3 is a detail of the means for predetermining the diaphragmsetting and subsequently bring the diaphragm to that setting.

As shown in Figure 1, the camera comprises the usual casing I,extensible bellows 2 and a lens and diaphragm holding casing 3 at theouter end of the bellows. On top of the casing is a focussing hood 4 andat the rear is a suitable holder 5 for light sensitive material, which,in the case illustrated, is in the form of a film.

Fixed on the outer end of a shaft 54 extending through the side wall ofthe casing is a lever 55 which, upon depression from its full line toits dotted line position, operates the shutter mechanism of the camerathrough the arm 52 of the bell crank 53 and the link 49 (Fig. 3) whichis connected to such mechanism.

The diaphragm setting mechanism is illustrated in Figures 2 and 3. Fixedto the end of a rod 11, which extends longitudinally of the camera, isan arm 18 connected by means of a link 19 to the diaphragm setting ringof the camera. I When the parts are in the full line position shown inFigure 2 the diaphragm is adjusted to its largest opening, while whenthey are in the dotted line position of that figure, the diaphragm isadjusted to its smallest opening. The rod 11 is slidable in and keyed toa sleeve 8| rotatably carried in a transverse wall 82 of the casing andin a bearing 83. The rod thus turns withthe sleeve but may slide throughit as the bellows 2 is extended or collapsed.

The sleeve 8| is adapted to be turned by movement of the bell crank 53fixed to the inner end of the shaft 54. An arm 81 of this bell crank isconnected by means of a link 88 to the outer end of an arm 84 which canturn freely on the sleeve 8| but is connected to the latter by a spring85 having one end secured to the arm and the other end to a collar 86 onthe sleeve. The strength and tension of the spring 85 are so adjustedthat unless the sleeve 8| is positively prevented from turning, anyturning movement of the arm 84 will turn the sleeve correspondingly. Thebell crank 53 is normally held by the spring 54a in the position shownin dotted lines in Figure 3. When the bell crank is in this position, itacts through the link 88, arm 84, spring 85, sleeve 8| and rod 11 tohold thearm l8 and link 19 in the full line position of Figure 2 andthus to keep the diaphragm adjusted at its maximum stop. Provided thatthe sleeve 8| and thus the rod 11 are not prevented from followingmovement of the arm 84, movement of the bell crank 53 from the dottedline to the full line position ofFigure 3 will move the parts 18 and 19to the dotted line position of Figure 2 and will thus reduce thediaphragm opening to its minimum.

The extent to which the diaphragm opening will actually be alteredduring such movement of the bell crank 53 is determined by theadjustment of a slide 94, which is movable in rails and 96 to an extentgoverned by the coaction of slots 91 in the slide and pins 98 on theside wall of the casing the two extreme positions of the slide beingshown respectively in full and dotted lines in Figure 3. The slide has aforward inclined face ")2 which lies in the path of turning movement ofan arm 89 fixed to the sleeve 8|. When the bell crank 53 is in itsnormal dotted line position, the outer end of the arm 89 lies in anopening |0| in the bottom rail 98 for the slide. If the slide is in thedotted line position, then it will prevent any movement of the arm 89,with the result that all movement of the arm 84 will be absorbed intightening the spring 85 and the sleeve M will stay still. On the otherhand, when the'slide 94 is in itsifull line position, movement of thearm '89 and thus of the sleeve 8| is not interfered with at all, as thearm 89 strikes the inclined face I02 only as the link 88 com-- adiaphragm opening scale 99. The indicator is fast to the outer end of ashaft 9| extending:

through the Wall of the-casing I and having fixed to its innerv end anarm 92 with a forked end which. embraces a pin 93 on the slide. When theindicator '90. is in the position shown in Figure 1 thearm- 92 is in theiullline position of Figure 3, whilewhen the indicator is at the extremeright ofv the scale the-arm 92 is in the dotted line position ofJFi'gure3.

If..a. picture is to be taken at a stop of, say ill, the. indicator 903is moved to the appropriate point on thescale'99. It will be appreciatedthat, becausethe end of the armi89 normally lies in the openinglflll inthe rail 96, this movement and the resultant movement of the slide 94causes'no movement. of the diaphragmsetting ring, so that the diaphragmremains; open to its full extent for .focussing, When the photograph isto be taken, the operating lever 55 is depressed, thus turning, thecrank 53 towards the full line position'of Figure 3. The diaphragm isaccordinglywclosed to'the required extent but is then prevented from'closing further by engagement of the arm89 with the inclined face I02 ofthe slide .94. Continued movement of the crank 53 merely tightens thespring 85 and finally, when the 10st motion in the connection 49a hasbeen taken up, moves the link 49 connected to the 4 shutter mechanism totrip the latter. When the lever is released, the diaphragm returns toits maximum opening ready for focussing and upon the taking of the nextphotograph will again'be closed to the same stop unless in the meantimethe indicator has'been moved.

This application is a division of my co-pending application Serial No.483,771, filed April 20, 1943'.

What I claim as my invention is:

A camera comprising an adjustable diaphragm, a shutter, a lost motionshutter tripping mechanism; a longitudinally extending rod soconnectedto'thediaphragm that rotation of the rod varies the diaphragmopening, a resilient connection. between said rod and said shuttertripping mechanism sufficiently strong to rotate said rod uponmovement01'- said mechanism in the absenceofobstruction to such rotation, meansfor predetermining the size-of the diaphragm openingv without moving thediaphragm,rsaid means including a manually adjustable. diaphragm openingindicator unconnected with the. diaphragm, an arm rotatable with therodnnd'iextending radially therefrom, a slide movable par.- allel to therod and having an inclined face against which said arm is adapted tostrike. and means connected to the indicatorformoving the slideto varythe point on said face against which said'arm strikes.

HAROLD PEARCE;

REFERENCES CITED The following referencesare. of record. file of thispatent:

UNITED STATES PATENTS Number. Name. Date.

720,586 Holst ..Feb..1.7, 1903 716,021. Folmer ..D.ec.16,1902 907,486Felt .Dec. 22, 1908 2,311,822 Frankel Feh. .23,,1943 2,371,524 Kals Mar.15,1945 2,343,206 ,Rath Feb. 29;, .1944

